What problem can occur if the USB device has been removed from the Car Audio while playing music?

Removing USB device from Car Audio while playing music.
Please make sure to stop playback of USB device or switch to other SOURCE before removing the USB device. (It may damage the data in USB devices.)

In addition, please remove the DMP (Digital Music Player) after turning OFF the main unit (Car Stereo) as Please do not cancel the connection message may appear during USB connection, depending on DMP (Digital Music Player).